void limitHoles(GeometryCollection& polygon, uint32_t maxHoles) {
if (polygon.size() > 1 + maxHoles) {
std::nth_element(polygon.begin() + 1,
polygon.begin() + 1 + maxHoles,
polygon.end(),
[] (const auto& a, const auto& b) {
return signedArea(a) > signedArea(b);
});
polygon.resize(1 + maxHoles);
}
}
/**
* Prepares a geometry into a grid if it is too big geospatially to have a sensible local tangent plane
* We will also tile the geometry if it just has too many points to speed up the tesselator.
*/
void prepareForTesselation(Geometry* geometry, const SpatialReference* featureSRS, double targetTileSizeDeg, unsigned int maxPointsPerTile, GeometryCollection& out)
{
// Clear the output list.
GeometryCollection tiles;
unsigned int count = geometry->size();
unsigned int tx = 1;
unsigned int ty = 1;
// Tile the geometry if it's geospatial size is too large to have a sensible local tangent plane.
GeoExtent featureExtentDeg = GeoExtent(featureSRS, geometry->getBounds()).transform(SpatialReference::create("wgs84"));
// Tile based on the extent
if ( featureExtentDeg.width() > targetTileSizeDeg || featureExtentDeg.height() > targetTileSizeDeg)
{
// Determine the tile size based on the extent.
tx = ceil( featureExtentDeg.width() / targetTileSizeDeg );
ty = ceil (featureExtentDeg.height() / targetTileSizeDeg );
}
else if (count > maxPointsPerTile)
{
// Determine the size based on the number of points.
unsigned numTiles = ((double)count / (double)maxPointsPerTile) + 1u;
tx = ceil(sqrt((double)numTiles));
ty = tx;
}
if (tx == 1 && ty == 1)
{
// The geometry doesn't need modified so just add it to the list.
tiles.push_back( geometry );
}
else
{
tileGeometry( geometry, featureSRS, tx, ty, tiles );
}
out.clear();
#if 1
// Just copy the output tiles to the output.
std::copy(tiles.begin(), tiles.end(), std::back_inserter(out));
#else
// Calling this code will recursively subdivide the cells based on the number of points they have.
// This works but it will produces a non-regular grid which doesn't render well in geocentric
// due to the curvature of the earth so we disable it for now.
//
// Reduce the size of the tiles if needed.
for (unsigned int i = 0; i < tiles.size(); i++)
{
if (tiles[i]->size() > maxPointsPerTile)
{
GeometryCollection tmp;
downsizeGeometry(tiles[i].get(), featureSRS, maxPointsPerTile, tmp);
std::copy(tmp.begin(), tmp.end(), std::back_inserter(out));
}
else
{
out.push_back( tiles[i].get() );
}
}
#endif
}
inline GeometryCollectionBaseType::const_iterator range_begin(const GeometryCollection& gc) {return gc.begin();}
